Whenever I try to tell anyone what my job title is, nobody understands! I got so frustrated when I went to a geology conference and everybody kept asking me what my sign was! That’s not what I do! I’m pretty sure I’m a Virgo, but I have no idea what that means! The same thing happens when I meet astronomers. They keep assuming that I know stuff like the capital of Nebraska. I am not an astrologer and not a geographer, I’m an astronomer who is also a geologist.

Sometimes people just slip up even when they do know the difference. I had a pretty funny conversation with my grandparents when I tried to explain my job. Here’s pretty much how it went:

Me: “Grandpa, I’m not a cartoon artist. How’d we even get on that subject? I study things like volcanoes and craters. Geology. And I haven’t tried to draw Pluto. But there’s this spacecraft that’s headed to…oh, that Pluto.”

Grandma: “Oh, geometry, with the shapes!”

Me: “That’s mathematics, Grandma. I’m an exogeologist. That’s a combination of geology and astronomy. I look at space rocks.”

Grandma: “Like the astronauts got from the moon?”

Me: “Yes! Exactly!”

Grandpa: “That sounds fun.”

Me: “Yes, it ROCKS!”

Grandma: “So when will you be going to the moon?”

I hope this helps you to tell the differences between exogeology and completely different jobs. My grandparents finally understood after that long conversation, and I can usually get people to at least say it right. People who just haven’t heard of exogeology, or even geology or astronomy, are just part of the job. I can’t blame them really, although it is annoying. For now, I’m Petra Stone signing off. Exogeology ROCKS!

Whether Pluto is a planet or not is a topic that’s had a lot of controversy since the term “planet” was defined. According to the new definition, a planet must: (1) orbit the Sun, (2) be basically round, and (3) have “cleared the neighborhood” around its orbit. Pluto fits all the requirements except for having cleared the area. Since it’s not a satellite of something else, it’s now considered a dwarf planet.

Pluto has been considered a planet for long enough now though that many people are upset by reclassifying Pluto as a dwarf planet.

I wonder if getting a better idea of what Pluto is like will help settle the debate? The New Horizons probe’s mission is planned to explore the Kuiper Belt and Pluto. It’s scheduled to arrive on July 14, 2015, making a flyby. That’s pretty soon considering how long of a mission it is to get there! I can’t wait to find out what it sees. Meanwhile, the Hubble Space Telescope got some good photographs of Pluto changing seasons, and New Horizons made a flyby of Jupiter.

What do I think? I believe that dwarf planets should be considered a specific type of planet, like terrestrial planets and gas giants. They should be considered just as important as any other planets. But there’s a good reason for changing the definition of “planet”; there are so many dwarf planets still being discovered that the number of planets in the Solar System would be hard to keep track of. Besides, we need a way to distinguish between planets and asteroids, and dwarf planets are somewhere in between. No matter what the definition of planet is though, Pluto is still an important member of the Solar System.

You’re probably wanting to know, just what is it that exogeologists do? What do they look at? Why? And what do they find there? Well, let me start by giving you a tour of the Solar System.

The Solar System is a big place, and there’s still a lot we don’t know about it. But we do know where to start looking. We’ve found eight planets, some dwarf planets, comets, and numerous asteroids.

In our solar system we have, in order from the Sun: Mercury, Venus, Earth, and Mars, the inner or “terrestrial” (Earth-like) planets. These are all rocky planets that have similar geology to Earth. Then there is the asteroid belt, a ring of asteroids (big chunks of rock in a ring between the inner and outer planets) orbiting the Sun. And next out there are Jupiter, Saturn, Uranus, and Neptune, the outer or “jovian” (Jupiter-like, the gas giants) planets. And much further out, there is the Kuiper belt, a ring of asteroids and dwarf planets like Pluto and Eris. There also comets, which have orbits that take them very far from the Sun for years, and then for a short time bring them into the inner solar system. Comets are made of ice and rock, and are sometimes called “dirty snowballs” because of their composition.

And what about the Moon? Well, exogeologists also study Earth’s moon, as well as other planets’ moons. The Moon is covered in craters, made by meteorites (asteroids and other space rocks that hit another object). There are dark areas on the moon that don’t have many craters though, and those are called maria. A mare is a place where a large meteor hit and molten lava seeped up through cracks made by the impact, which then cooled to become one of the dark maria we see on the moon today.

Some of the other planets have moons too, in fact, Jupiter has 63 and Saturn has over 200! Moons can be very different from each other. Some have atmospheres (like Saturn’s Titan), and some are just asteroids and are strange shapes and have lots of craters (Like Mars’ two moons, Phobos and Deimos).

There are lots of planets to explore, and that’s what I do! I like finding out new information about everything in the solar system!